Aminosilane surfaces provide available amine groups for initial ionic attachment of the negatively charged phosphate groups in the DNA backbone. Conventional wisdom is that longer aminosilane molecules with multiple amino groups produce higher signal-to-background ratios, as their higher positive charge will bind more DNA to the slide surface. However, recent research at SCHOTT has shown that the situation is actually more complicated than this, and that while surfaces with a higher charge do bind more DNA, they are also more difficult to block effectively, resulting in significantly higher non-specific binding. The higher levels of non-specific binding have a negative effect leading to poorer signal-to-background ratios.
Comparison of aminosilane structures
The aminosilane slide offered by SCHOTT is based on very short chain aminosilanes that demonstrate high signal intensities, and exceptionally low background signals, when compared with other commercially available aminosilane slides.
Signal-to-background ratios compared to market leading aminosilane slide
Aminosilane coated slides have a high concentration of primary aminogroups available at the surface. These groups become protonated and therefore positively charged when placed in contact with a near-neutral, aqueous solution. Negatively charged probe molecules, such as DNA, will initially form multiple ionic interactions with the positively charged amino surface coating. Additional amino-modifications of the nucleic acids are not required, but such modifications do not interfere with the immobilization. After spotting, the probes are covalently linked to the slide surface by either heating, or a brief exposure to ultraviolet (UV) light. Other types of negatively charged biomolecules may also be coupled to aminosilane surfaces.
SCHOTT slides are manufactured from a high quality, low intrinsic fluorescence borosilicate glass. The glass slides are cleaned and coated in a class 100, environmentally controlled clean room to ensure contamination and artifact free surfaces. The aminosilane coatings are applied using a unique, and innovative method developed and optimized by SCHOTT, that allows the production of large lot sizes with excellent intra-lot, and inter-lot reproducibility. Each slide lot is tested using both physical and functional quality control checks. The density of the aminosilane groups in the coatings remain uniform over the entire surface of the slides, and is optimized to maximise the DNA binding capacity. The surface hydrophobicity is tightly controlled to optimize the performance with both contact and non-contact microarray printers. The Slide A+ surface is more hydrophobic than the AStar surface, resulting in smaller spots, making it ideally suited for printing higher density arrays.
NEXTERION® Slide A+, and Slide AStar are compatible with the most commonly used aminosilane protocols and a wide range of spotting buffers. This makes it easy to evaluate and switch to the NEXTERION® aminosilane slides from competitor slides.
Selecting the most suitable NEXTERION® aminosilane coating
Choosing the best SCHOTT aminosilane slide for the application depends on a number of factors. One important factor is the buffer used for printing the arrays. SCHOTT has developed a printing buffer system (NEXTERION® Spot A HD) for printing high-density arrays of up to 50k spots on the SCHOTT aminosilane slides. The buffer system is designed to minimize sample evaporation during long print runs.
Packaging and storage
NEXTERION® Slide AStar and A+ are packaged in specially developed compatible plastic boxes, and sealed under an inert atmosphere, to ensure the substrates have a long and stable shelf life. The slides should be stored at room temperature in the sealed packaging, and are ready-to-use from the box.
NEXTERION® Slide AStar and A+ are available in packs of 25-slides with optional code 128 barcodes enabling automated sample tracking. The AStar and A+ aminosilane coating are also available in 16-well slide, 48-well slide and 96-well microplate formats. For further information refer to the section on “Multi-well formats”.
SCHOTT Microarray Solutions offers a kit with pre-prepared reagents for the blocking, hybridization and washing of 25 aminosilane coated slides printed with oligonucleotides.
NEXTERION® Slide A+: DNA application
Protocol revisionMSDS NEXTERION® Aminosilane Coated Slides Download pdf file 'NEXTERION® Slide A+'
Date: April 2009
Protocol version: 1.4
Revision made: minor layout changes, new telephone and fax numbers
Revision reason: correction contact information
SCHOTT Technical Glass Solutions GmbH